Kinetics of glucuronide formation for selected xenobiotics in membrane preparations from HK293 cells stably expressing UGT2B9 protein
| Substrate | ApparentKM | Vmax | Vmax/KM(×100) |
|---|---|---|---|
| μM | pmol/min × mg | ||
| Naproxen | |||
| pH 7.5 | 368, 403 | 26, 24 | 7, 6 |
| pH 6.5 | 56, 62 | 40, 41 | 71, 66 |
| (R)-Ibuprofen | 117, 59 | 53, 45 | 45, 76 |
| (S)-Ibuprofen | 133, 54 | 218, 176 | 164, 326 |
| (R)-Propanolol | 390, 420 | 44, 50 | 11, 12 |
| (S)-Propanolol | 440, 375 | 18, 19 | 4, 5 |
| (+)-Menthol | 225, 148 | 129, 112 | 57, 76 |
| (−)-Menthol | 140, 161 | 372, 303 | 266, 188 |
Apparent KM values for the aglycone substrates were determined at pH 7.5, unless otherwise noted, using 2.0 mM UDP-glucuronic acid. Results are expressed as the individual values obtained using membrane preparations from different passages of cultured cells.